Urinary incontinence affects millions of men and women of all ages in the United States. Stress urinary incontinence (SUI) affects primarily women and is generally caused by two conditions, intrinsic sphincter deficiency (ISD) and hypermobility. These conditions may occur independently or in combination. In ISD, the urinary sphincter valve, located within the urethra, fails to close properly (coapt), causing urine to leak out of the urethra during stressful activity. Hypermobility is a condition in which the pelvic floor is distended, weakened, or damaged, causing the bladder neck and proximal urethra to rotate and descend in response to increases in intra-abdominal pressure (e.g., due to sneezing, coughing, straining, etc.). The result is that there is an insufficient response time to promote urethral closure and, consequently, urine leakage and/or flow results.
A popular treatment of SUI is the use of a sling, which is permanently placed under a patient's bladder neck or mid-urethra to provide a urethral platform. Placement of the sling limits the endopelvic fascia drop, while providing compression to the urethral sphincter to improve coaptation. Further information regarding sling procedures may be found, for example, in the following: Fred E. Govier et al., “Pubocaginal slings: a review of the technical variables,” Curr. Opin Urol. 11:405-410, 2001, John Klutke and Carl Klutke, “The promise of tension-free vaginal tape for female SUI,” Contemporary Urol. pp. 59-73, October. 2000; and PCT Patent Publication No. WO 00/74633 A2: “Method and Apparatus for Adjusting Flexible Areal Polymer Implants.”
Unfortunately, permanent placement of a sling in a patient's periurethral tissues may cause complications necessitating further surgical intervention. For instance, changes in a patient's body weight and/or anatomy over the course of his/her life, may cause the sling to contact the patient's urethra. This is an undesirable side effect that may result in discomfort and more serious medical problems such as urethral erosion for the patient. As further examples of undesirable side effects, a patient with a sling permanently placed in her periurethral tissues may suffer vaginal mucosal erosion of the vaginal incision that is made during sling implantation, permanent urinary retention, or both. These complications require further surgical intervention to resect the sling. See, e.g., B. G. Volkmer et al. J. Urol., Vol. 169, February 2003, pp. 570-4.
Due to deficiencies in the prior art, improved surgically implantable slings are needed.